Exactly what does rdev -R do?

[Mitchell Gil Maltenfort]

I was reviewing the linux-newbies FAQ and the discussion of how to make a
boot disk.  I've also compared it to the HOWTO for making a boot disk,
http://metalab.unc.edu/mdw/HOWTO/Bootdisk-HOWTO.html, and I am confused.

If I type rdev-R /dev/fd0 1, exactly what does that do?  Tell the floppy
it's the boot disk?  Tell my Linux box that the floppy is a boot disk?  

I checked the man pages and rdev-R isn't even listed.  

I already created a boot disk with mkbootdisk, but I assume this is a
non-standard feature of RH5.2, and I'm wondering what I really need to do.  

Thanks in advance.